Re: Linux PV domU with >1 vCPU never resumes after xl save/restore

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On Tue, Aug 4, 2026 at 6:02=E2=80=AFPM Jan Beulich <[email protected]> wrot=
e:

> On 04.08.2026 08:12, George Dunlap wrote:
> > Saving and restoring a multi-vcpu PV guest appears to have been broken =
in
> > Linux for some time (observed 6.6.56 and 6.12.86).  Report below from
> > Claude Fable; I've independently verified the behavior on vanilla Linux
> > 6.6.56.  Claude seems to think it's a bug in Linux.
>
> Just to double check, as there was a crucial fix there recently: This is
> with
> a Xen including bedbc17d8407 ("x86/domctl: restore all registers in
> arch_{get,set}_info_guest()")?
>

Ah, yes, that seems to have done the trick.  Sorry for he noise.

 -George

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<div dir=3D"ltr"><div dir=3D"ltr"><br></div><br><div class=3D"gmail_quote g=
mail_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">On Tue, Aug 4, =
2026 at 6:02=E2=80=AFPM Jan Beulich &lt;<a href=3D"mailto:[email protected]=
">[email protected]</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quot=
e" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204)=
;padding-left:1ex">On 04.08.2026 08:12, George Dunlap wrote:<br>
&gt; Saving and restoring a multi-vcpu PV guest appears to have been broken=
 in<br>
&gt; Linux for some time (observed 6.6.56 and 6.12.86).=C2=A0 Report below =
from<br>
&gt; Claude Fable; I&#39;ve independently verified the behavior on vanilla =
Linux<br>
&gt; 6.6.56.=C2=A0 Claude seems to think it&#39;s a bug in Linux.<br>
<br>
Just to double check, as there was a crucial fix there recently: This is wi=
th<br>
a Xen including bedbc17d8407 (&quot;x86/domctl: restore all registers in<br=
>
arch_{get,set}_info_guest()&quot;)?<br></blockquote><div><br></div><div><sp=
an style=3D"background-color:transparent">Ah, yes, that seems to have done =
the trick.=C2=A0 Sorry for he noise.</span></div><div><span style=3D"backgr=
ound-color:transparent"><br></span></div><div><span style=3D"background-col=
or:transparent">=C2=A0-George=C2=A0</span></div></div></div>

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